Genomic mechanisms of transformation from chronic obstructive pulmonary disease to lung cancer.

Genetic variations in COPD and lung cancer may be one of the molecular mechanisms responsible for COPD-lung cancer transformation. The present review highlights main genetic variations co-existed in COPD and lung cancer and integrates the varied genes into four molecular mechanisms, e.g. activated cell proliferation pathway, tumor suppressor and DNA repair gene dysfunction, chronic inflammatory microenvironment, and impaired immune response, by which COPD epithelial cells may be transformed into tumorigenic status. We call special attention to further investigate the transformation from COPD to lung cancer and understand the exact molecular mechanisms, to prevent and reduce the increased incidence of COPD and lung cancer. We call direct evidence to show the existence of COPD-lung cancer transformation, since current evidence to support the transformation from COPD to lung cancer is the co-existence of selected genes and proteins in both. We should furthermore explore and understand the homogeneity and heterogeneity of gene mutation, epigenetics, sequencing, and function between COPD and lung cancer. The defining and understanding of COPD-lung cancer transformation will provide new diagnostic and therapeutic biomarkers as a new milestone to prevent and treat lung cancer.